1. Field of the Invention
This invention relates to hydrostatic bearings and more particularly to hydrostatic bearings having two pads with axial grooves to improve dynamic stability.
2. Description of Related Art
Hydrostatic bearings have been in use for many years. One of the problems encountered with hydrostatic bearings are their stability characteristics. Hydrostatic bearings journals tend to whirl which is an undesirable feature. One of the factors which limits the speed at which a hydrostatic bearing can operate is the whirl frequency ratio, therefore reducing the whirl frequency ratio is a long sought desired end. As the whirl frequency ratio increases the damping capability of the hydrostatic bearing decreases. Many techniques have been introduced to reduce the whirl frequency ratio, among them are roughened bearing surface walls, non-rectangular recess geometries, liquid injection opposite to shaft rotation, increased recess edge downstream losses, and discharge wear rings or end seals. However these techniques all try to reduce the development of circumferencial flow velocity which yields the undesired cross-coupled stiffness coefficients.